Link: https://www.nytimes.com/interactive/2020/us/elections/delegate-count-primary-results.html
NY Times is doing an interesting continuous story with data. This one, while not investigative, helps break down how exactly primary delegates work. I also like that it's not one-and-done. It's mean to be updated as the primary elections roll on. They also went a little deeper by including the 2016 results for comparison. That will not only keep people coming back to the story to see what's changed, but also makes the elections easier to understand.